According to certain prior art proposals chain-type gear devices are provided wherein a chain is stretched over an outer tooth wheel, and strained less than its elastic limit to thereby provide a rigid type of gear device for meshing with the teeth on a smaller tooth wheel disposed internally thereof. This technique works quite well in many applications and is especially an advantage over other chain-type gear devices wherein there is a certain amount of flexibility inherent in the device. The so called strained device was an advance in the art in so far as it removed this flexibility, thus reducing the tendency of the chain to skew or become improperly aligned under heavy loads.
However, even the strained chain device has a certain tendency to skew or twist under loading, especially in very heavy load applications over an extended period of time. This is particularly true when there is required a rather wide chain to provide the proper size for the smaller tooth wheel, necessitating a rather long centilevered sipport, thereby creating a great opportunity for skewing or canting even when the chain was stressed is being applied. Thus, while the strained chained device is an improvement over other prior art chain-type gear devices, there still are certain areas where it is not entirely satisfactory.